This application is based on and claims priority of Japanese Patent Application No. 2001-69105 filed on Mar. 12, 2001, the contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to an endoscope that allows an operator to observe the form of an inserted part of the endoscope through detection of the magnetic filed generated by magnetic field generating coils placed inside of the insertion section of the endoscope by an endoscope form detecting apparatus.
2. Description of the Related Art
Generally, the insertion section of an endoscope comprises, from the proximal end, a tubular section, a curving section and a distal end structural section. The tubular section is elongate and flexible. The distal end section contains an optical system for illumination and an optical system for observation.
When an operator inserts the insertion section into a body lumen, he or she controls the curving section to bend following the curve of the lumen while he or she gradually inserts the insertion section into the deep portion of the body lumen.
When the lumen that the insertion section is inserted into has complicated curves, like a colon or a small intestine, it is difficult for the operator to know how the curving section bends.
To know the form of the insertion section during the operation, Japanese Patent Laid-Open Publication No. 2000-93386 discloses an endoscope that has a probe with a plurality of magnetic coils placed along the axial direction of the endoscope to generate magnetic fields, these coils are for detecting the form of the insertion section. This endoscope generates an image signal representing the form of the insertion section by detecting the magnetic fields generated by each of the coils using an apparatus located outside of the endoscope, and sends the image signal to a display to show the form of the inserted section.
However, the probe for detecting the form of the insertion section placed inside of the endoscope has a rather large outer diameter. Because of this large diameter, the endoscope having the probe inside tends to have a high contents filling rate at the cross-section area of the insertion section tube. The contents filling rate is a rate of the total cross-section area of all contents of a tube per a cross-section area of inside of the tube at predetermined part of the tube. The term xe2x80x9ccontentsxe2x80x9d covers all objects inside of the tube. For example, the contents may include optical lenses for an optical observation system, CCD camera for detecting an image taken by the optical lenses and signal lines of the CCD camera which run toward a proximal portion in the insertion portion. The contents may also include optical fibers running from a proximal portion of the insertion section to a distal portion of it that directs illuminating light to the distal end of the insertion section. The contents may also include an air/water supply tube for supplying air and water to the distal portion of the insertion section. The air/water supply tube comprises a nozzle and a tube, the tube is connected to the nozzle and runs toward the proximal part of the insertion section.
An air/water supply channel branch is a part where the air/water supply channel is connected to an air supply channel and a water supply channel to fluidly communicate with each other. Because the air/water supply channel branch has a large volume, when it is placed inside of the insertion section, the contents filling rate of this part will be locally high. Therefore, the contents are pressed by one another and the friction rate among the contents is increased. In such a situation, the movements of the contents are hampered, and the durability of the endoscope is decreased.
In many cases, the tubular section, which is a part of the insertion section, has a spiral tube in the innermost layer. The spiral tube is formed of a spirally wound metal tape. This spiral tube has gaps of predetermined width between each wind of the metal tape. The curving section, which is also a part of the insertion section, has a curving tube in the innermost layer. The curving tube is formed of many short cylindrical tubular bodies rotatably jointed each other in series. This curving tube has gaps of predetermined width between each cylindrical tubular body. As the probe has a larger outer diameter at the coil portions, if the coil length in a longitudinal direction is shorter than the gap width of the spiral tube or the gap width of the bendable section, the coil portions of the probe will engage into these gaps. This engagement may prevent the probe to move smoothly in the longitudinal direction, and damage may the probe or the other contents.
In view of the forgoing, an object of the invention is to provide an endoscope having a good durability.
The present invention provides an endoscope. The endoscope comprises an insertion section for being inserted into the body cavity; a probe provided inside said insertion section for detecting the form of said endoscope. The probe includes a plurality of coil portions arranged in the longitudinal direction of said insertion section of said endoscope, a wire electrically connecting said plurality of coil portions and a flexible member covering said coil portions and said wire. The cross section area of said covered wire is smaller than the cross section area of said covered coil portions.
Furthermore, an endoscope of the present invention comprises an insertion section for being inserted into the body cavity; a probe provided inside said insertion section for detecting the form of said endoscope. The probe includes a plurality of coil portions arranged in the longitudinal direction of said insertion section of said endoscope, a wire electrically connecting said plurality of coil portions and a flexible member covering said coil portions and said wire. The cross section area of said covered wire is smaller than the cross section area of said covered coil portions. A device is located outside the body, for detecting the magnetic field generated from said probe or for generating the magnetic field to be detected by said probe. A processor is provided for calculating the form of said endoscope insertion section on the basis of the magnetic field detected by said probe or said outside device. A monitor is provided for displaying the form of said endoscope insertion section on the basis of a result calculated by said processor.